1. Field of the Invention
The invention relates to an assembly and a method for aligning a light beam that is exiting from a light source or from a light guide.
2. Description of Related Art
Light beams that are exiting from a light guide or a light source, for example an optical fiber or a laser diode, usually exhibit divergent or diffuse beam characteristics. For many applications, however, focused or collimated light beams are required, so that an output beam is often shaped using optical lenses or sets of lenses. Beam shaping optics may be installed in an housing which is coupled to the end of a light guide, in the form of a plug, for example. Also, a housing with beam shaping optics may be used as a mounting support for installing a light source, e.g. a laser diode, especially for producing laser modules with predetermined beam characteristics.
U.S. Pat. No. 6,801,688 B1, for example, describes a collimator that receives light from an optical fiber and generates a collimated light beam at an increased specified diameter. The fiber optic collimator has a shuttle plug for receiving the optical fiber, and the shuttle plug is arranged to be movable in an axial direction in a collimator housing.
U.S. Pat. No. 6,168,319 B1 discloses a collimator assembly with an optical fiber and a graded-index lens, wherein the components are mounted within a thin tube. The distance between the fiber and the lens is varied so as to obtain a predefined beam width.
U.S. Pat. No. 4,431,267 describes an optical system for providing a collimated light beam, in which a semiconductor laser is positioned against an abutment in a tubular holder. A system of lenses can be moved against a pressure of a resilient element in direction of the laser, and when a collimated light beam is generated, a locking element is fixed so that the system of lenses is correctly adjusted.
In the case of collimators of the type described above, but also in systems of different types, e.g. in the case of fiber plugs, inaccuracies in the beam exit angle may arise due to the manufacturing tolerance of all components. Sometimes, the optical axis of the exiting light might be tilted relative to the mechanical housing axis, by about a few milliradians (mrad) or more. Since many applications require a beam that is aligned more accurately, it would be desirable to avoid such errors.
International patent application WO 2011/026770 A1 describes a collimation device which permits to adjust the direction of the beam. The assembly comprises a stationary plate supporting a beam source, and a movable plate on which a collimator optic is mounted.
International patent application WO 2012/112146 A1 describes a beam coupler assembly with a lens housing adjustment system that maintains the adjustment of the x- and y-axes while allowing movement in the z-direction with little effort.
However, the items disclosed in the aforementioned documents are configured for special requirements and are rather complex. In addition, they are not eligible for many applications.